Blake Farenthold was all smiles on Election Day 2010. (Facebook photo)

A field of Democrats seeking to challenge Republican Rep. Blake Farenthold or his GOP rival grew Monday and ensured a spirited primary battle regardless of federal court scrutiny over a controversial redistricting map.

Denise Saenz Blanchard of Brownsville, a past congressional aide, filed for the seat once held by her boss, former Rep. Solomon Ortiz, D-Corpus Christi, in the 27th Congressional District.

She follows Nueces County Democratic Party Chairwoman Rose Meza Harrison of Corpus Christi, who entered the race last week.

Blanchard and Harrison join two other hopefuls, former Edinburg City Manager Ramiro Garza and Armando Villalobos, the Cameron County district attorney, who have announced their intentions to seek the Democratic nomination for the congressional seat.

The four Democrats are vying for a chance to square off with Farenthold, who faces Don Middlebrook of Louise in the GOP primary. Farenthold shocked South Texas political circles in 2010 when he unseated Ortiz after 28 years in Congress.

Farenthold “was the big surprise winner last time,” said Kyle Kondik, a political analyst at the University of Virginia.

The number of hopefuls seeking the opportunity to challenge Farenthold shows that a court-drawn redistricting map is likely favorable to Democrats, Kondik said.

It’s probable that even under a Republican-drawn map by the Legislature, “the Democrats would have tried to take a shot at it,” Kondik said.

The Democratic and Republican parties have agreed to hold primaries April 3, a month later than originally scheduled.

The parties also agreed that candidates will be allowed to switch congressional districts if the court challenges alter congressional lines.

Another congressional incumbent, Rep. Ruben Hinojosa, D-Mercedes, faces stiff opposition in his own party primary, in which three challengers are seeking the party nomination in the 15th Congressional District.

Hinojosa faces Ruben Ramirez of McAllen, Jane Cross of Edinburg and rancher David Cantu of San Juan.

Jim Kuiken of McAllen, Eddie Zamora of Edinburg and Dale Brueggemann of Seguin are seeking the Republican nomination in the 15th District.